English：

To study the deformation characteristics of the supporting underground diaphragm wall in thedeep foundation excavation in Foshan soft soil area, taking the deep foundation excavation of the LüdaoLake North Station of Foshan Subway Line 4 as the engineering background, the deformation law andinfluencing factors of the supporting structure and the surrounding environment during the excavation ofthe foundation excavation are analyzed by simulation and field measurement. The results indicate that theretaining structure of the foundation excavation is shifted to the outside of the foundation excavation in theshallow depth. With the increase in the excavation depth, the lateral displacement of the retainingstructure of the foundation excavation increases continuously, and the maximum lateral displacementposition of the foundation excavation remains unchanged, which is located in the depth range of 10 ~20m. The settlement of the surface around the foundation excavation increases first and then decreaseswith the increase in the distance, reaching the maximum settlement value when the distance from thefoundation excavation is 20~30m. Therefore, the principles of fast support and fast excavation should befollowed in the excavation of foundation excavations in weak composite strata. If necessary, temporarysupport can be set up quickly when the foundation excavation is at the bottom, which is helpful fordeformation control.